In known warp machines of this type, the compression element, which is necessary particularly in the warping of elastic or viscous warp threads, consists of a compression cylinder which is rotatably mounted on a pivotable holder and is of an axial length so as to approximately coincide (except for a small amount--about 2-3 mm of axial play) with the inner axial spacing of the warp beam discs from each other. Because the width of the compression cylinder must engage between the warp beam discs and come to rest against the spool element, it has a relatively large diameter, especially because its rotary axis must lie outside the radius of the warp beam discs. In other words, the compression cylinder must have a radius that at least equals the radius of the warp beam discs minus the radius of the spool element. However, this large diameter also leads to certain disadvantages, for example, even with the use of a hollow cylinder, when handling a large mass or gyrating mass whereby the operating speed of the machine is severely limited by the resulting unacceptably high centrifugal forces, it is necessary to brake the compression cylinder. Additionally, the large compression cylinder requires a large amount of space even when it is retracted from the warp beam, which alone results in the warp machine having disadvantageously large dimensions. Further, it is disadvantageous that each given warp beam length or width requires a specific associated compression cylinder, which because of the large dimensions of the compression cylinder, leads to expensive storage arrangements and greater expense in work and time in conversion work when a warp beam is changed.
A solution for reducing the diameter of the compression cylinder has long been sought. It is known, for example, to hinge the compression cylinder to at least one mounting arm which engages with one truncated end between the warp beam discs. In such a system, the truncated end portion of the mounting arm is arranged within a depression formed in the front side of the compression cylinder. This makes it possible to place the rotary axis of the compression cylinder in the area lying between the warp beam discs, so that the diameter of the compression cylinder can be somewhat reduced. Such a measure immediately faces a limitation however, because the truncated end portion of the mounting arm must in any case be located within the depression in the compression cylinder, i.e., the diameter of the depression can not be smaller than the length of the truncated end portion of the mounting arm.